DEONTAY WILDER suffered his bicep injury before his defeat to Tyson Fury, his sparring partner claimed.
The Bronze Bomber was hindered by the arm problem during his rematch with the Gypsy King in February.
Fury took full advantage as he battered the previously-unbeaten WBC heavyweight king, sensationally stopping him in the seventh round.
Wilder – also hindered by his ridiculous £31,000 ring-walk costume – underwent secret surgery on the troublesome bicep after the fight.
But Junior Fa, who was part of the American’s training camp, revealed the injury was sustained before the Las Vegas showdown.
The New Zealander told Sky Sports: “I was very shocked [by the Wilder defeat]. The lead up and the training was actually really good and Deontay was looking great.
“I think he did hurt himself towards the end of camp, which I don’t think would have played too much into the fight, but then I don’t really know the extent of the damage of the injury that he sustained.”
Asked about the specifics of Wilder’s injury, the 19-0 Fa added: “Yes, the bicep injury. I don’t know the extent of the damage, but he did hurt it, yeah.
“What I do know [is] that he did get injured, but I was very surprised by Fury’s game plan.
“As soon as the fight started, and I saw Fury not really taking a backward step, trying to push Wilder to the ropes, I was thinking, ‘Oh man, this is going to be a hard night for Wilder.’
“Fury just basically did what he said he was going to do, which was stop the biggest puncher in the world. That was a very, very good performance from him.”
WBO Oriental interim heavyweight holder Fa, 30, is hoping to secure a bout with compatriot and former WBO champ Joseph Parker in the coming months.
But the 2011 Commonwealth bronze medalist has also sparred with Anthony Joshua on multiple occasions – albeit during AJ’s amateur days and prior to his 2012 Olympic glory.
Fa admitted both Joshua and Wilder have terrifying power, but the Bronze Bomber just edges it.
He said: “I sparred AJ before we knew how good he was, so back in 2011 just after the Commonwealth Games.
“Good timing, good power. Very, very good power. He’s very, very focused and very dedicated to the sport.
“From what I can remember, from AJ in terms of comparing power, I would say definitely Deontay Wilder is the biggest puncher.
“It’s just a different type of power. I can’t really explain it.
“I know AJ has got serious heavy hands and they’ve got a bit of a snap to it too, but Wilder, I don’t know man, he’s just got a punch that dazes you straight away.”